共查询到19条相似文献,搜索用时 93 毫秒
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以丝瓜络为炭源、浓硫酸为磺酸化试剂,制备了丝瓜络炭磺酸催化剂。利用中和滴定、X射线衍射、傅里叶变换红外光谱和热重-差热分析等手段对催化剂进行了表征。以表面酸密度为考察指标,确定了在300℃炭化3h、在80℃下磺化3h为优化的催化剂制备条件,此条件下丝瓜络炭磺酸催化剂表面酸密度可达1.119mmol/g。以木糠水解制备糠醛为探针反应,通过正交实验法考察了催化剂的实际催化活性。结果表明,在水解反应时间2h、水解反应温度200℃和催化剂用量占原料质量10%时,糠醛的平均收率达到78.69%,此时催化剂的催化活性最高。催化剂经第一次循环使用后性能有所下降,但随后的循环使用催化性能稳定。将使用过的催化剂经再磺化,可基本恢复到新制催化剂的催化活性。 相似文献
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采用等体积浸渍法制备了一系列催化剂用于甲烷氮气常压合成氨反应.对Si O2、γ-Al2O3、煤质柱状炭、椰壳活性炭为载体的Fe基催化剂的活性评价结果显示椰壳炭载体最优;通过对Zr、Ce、K等多种助剂的筛选,发现K促进的Fe基催化剂氨生成速率最高.利用XRD、SEM、BET等手段对载体和催化剂进行表征,结果表明椰壳炭具有规则孔道且孔容增大,催化剂还原后有新晶相KFe O2生成.最后在固定床微分反应器中,考察了常压合成氨催化剂的负载顺序及最优工况.结果表明,在常压700℃、VCH4/VN2=2/1、空速为2 800 m L/h时,催化剂3%K-5%Fe/椰壳炭的氨生成速率最高可达1.04×10-6mol·g-1·s-1,是现有文献值的83.5倍,将具有深远的工业应用前景. 相似文献
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以对叔丁基苯酚为原料,经环化缩合、脱叔丁基、酚羟基醚化、甲酰化和氧化反应制得5-羧基-25,26,27,28-四正丙基杯[4]芳烃(5);5与O-苄基-N-苄氧羰基丝氨酸反应制得5-(O-丝氨酸)-25,26,27,28-四正丙基杯[4]甲酸酯(7),其结构经~1H NMR,~(13)C NMR和MS(ESI)表征。研究了溶剂和水的用量对7催化性能的影响。结果表明:水为溶剂,其用量为10 eq.时,收率和非对映选择性分别为95%和3∶97 dr;当水的用量为30 eq.时,收率和非对映选择性分别为93%和98∶2 dr。 相似文献
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纳米Co3O4的制备及其对高氯酸铵热分解的催化性能 总被引:5,自引:0,他引:5
选用CoCl2·6H2O分别与NaOH, H2C2O4·2H2O, Na2CO3·10H2O及Na2C2O4组成四个反应体系,通过室温固相反应制备了不同平均粒径的纳米Co3O4, 并用X射线衍射和透射电镜对Co3O4的物相、形貌和粒径大小进行了表征. 结果表明, Co3O4的平均粒径分别为23, 30, 35和150 nm, 大小均匀,分散性好. 还用差热分析法考察了纳米Co3O4对高氯酸铵热分解的催化性能,并与微米Co3O4进行了比较. 结果表明,纳米Co3O4可使高氯酸铵的低温放热峰消失,高温放热峰温度降至323.5 ℃, 降低了128.5 ℃, 表观分解热增加了750 J/g, 达 1265 J/g, 纳米Co3O4对高氯酸铵热分解的催化性能明显好于微米Co3O4. 相似文献
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制备了碱性离子液体1,1'-(丁烷-1,4-二基)双(1,4-二氮杂二环[2.2.2]辛烷-1-ium)羟化物,并采用红外光谱、1H核磁共振谱和pH值分析对其进行了表征.然后将它用于室温研磨条件下高效催化合成吡喃酮[2,3-d]嘧啶酮和[2,3-d]嘧啶.该法步骤简单,反应时间短,产物收率高,无需柱色谱分离,原料易得,且可回收利用. 相似文献
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E. L. Gavrilova A. A. Naumova A. R. Burilov M. A. Pudovik E. A. Krasil’nikova A. I. Konovalov 《Russian Chemical Bulletin》2007,56(11):2348-2350
Reaction of resorcinarenes with 4-phosphorylbenzaldehydes afforded calix[4]resorcinarenes, bearing phosphorylaryl substituents
at the lower rim of the molecule.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2269–2271, November, 2007. 相似文献
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Peyman Sakhaii Ion Neda Matthias Freytag Holger Thnnessen Peter G. Jones Reinhard Schmutzler 《无机化学与普通化学杂志》2000,626(5):1246-1254
The acid‐catalyzed (with HCl) condensation reactions of resorcinol ( 1 ) with 1‐naphthaldehyde ( 2 ) and isobutyraldehyde ( 3 ) furnished the tetrameric macrocyclic compounds 4 and 6 . Detailed NMR‐investigations of the acetylated tetrameric species 5 surprisingly support a structure not in agreement with the expected all‐cis conformation. The chair conformation (C2h symmetry) of the acetylated derivative 5 was established through a crystal X‐ray diffraction study. The naphthyl substituents are arranged in trans position above and below the plane made up by the resorcinol units. The reaction of resorcinol 1 with isobutyraldehyde, in accord with expectation, led to the calix[4]resorcinaren ( 6 ). The 1H NMR spectra of compound 6 and 7 appeared at room temperature as broad signals, indicating a conformation of C2v symmetry. The reaction of the C‐methyl‐tetrakis‐P‐(chlorodioxaphosphocin)‐calix[4]resorcinarenes ( 8 ) and ( 10 ) with suitable N‐trimethylsilyl organic amines were conducted in tetrahydrofuran suspension, furnishing the P–N‐substituted calix[4]resorcinarenes ( 9 ) and ( 11 ). While in the complexation of C‐methyl‐tetrabromotetrakis‐P‐(dimethylaminodioxaphosphocin)‐calix[4]resorcinarene ( 13 ) with (tht)AuCl (tht = tetrahydrothiophene) the expected, neutral tetra‐substituted complex 15 was formed, the reaction of 13 with moist acetonitrile led to the anionic atomic framework 14 . X‐ray structure determinations of the complexes 14 and 15 show that both possess the cone conformation. In the gold complex 15 , the Au–Cl groups form a loose aggregate, with three Au…Cl contacts of 316–340 pm; one of the groups points towards the centre of the cone. The copper(I) complex 14 displays crystallographic mirror symmetry, with a central Cu4Cl5 unit involving tetrahedrally coordinated copper. 相似文献
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Sergey N. Podyachev Viktor V. Syakaev Svetlana N. Sudakova Roald R. Shagidullin Darya V. Osyanina Ludmila V. Avvakumova Boris I. Buzykin Shamil K. Latypov Ingmar Bauer Wolf D. Habicher Alexander I. Konovalov 《Journal of inclusion phenomena and macrocyclic chemistry》2007,58(1-2):55-61
A series of new calix[4]phenols, calix[4]resorcinols and calix[4]pyrogallols with acetylhydrazide substitutes has been␣synthesized
with high yields by hydrazinolysis of ester group containing calix[4]arenes. The synthesized calix[4]phenols adopt the cone
conformation while the calix[4]resorcinol and calix[4]pyrogallol derivatives prefer the boat conformation. The amide fragment
of the hydrazide groups predominantly exists in the trans-conformation. The binding ability of synthesized calix[4]arenes toward transition and alkali metals by solvent extraction
has been investigated. 相似文献
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Five novel azo calix[4]arenes were reported. The p-aminobenzaldehyde was diazotized with sodium nitrite in aqueous hydrochloride solution. Mono-, bis-, tris- and tetrakis(p-formylphenyl)azo calix[4]arenes (including proximal and distal isomers) were obtained respectively by diazo-coupling in different molar ratio to calix[4]arene(1) under pH=7.5--8.5 at 0-5℃. All (p-formylphenyl)azo calix[4]arenes were characterized by ^1H NMR, ^13C NMR, IR, MS (ESIMS) spectroscopies and elemental analysis. 相似文献
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Synthesis of calix[4]resorcinarenes,containing phosphoryl fragments at the lower rim of the molecule
A. R. Burilov I. R. Knyazeva Yu. M. Sadykova M. A. Pudovik W. D. Habicher I. Baier A. I. Konovalov 《Russian Chemical Bulletin》2007,56(6):1144-1148
Reaction of resorcinol with phosphorylated acetals or ethoxyvinylphosphonic acid esters in acidic media leads to calix[4]resorcinarenes,
containing dialkoxyphosphoryl fragments at the lower rim of the molecule. When the alkyl substituent in alkoxy groups at phosphorus
atom is not very long, a partial hydrolysis of the initially formed products takes place to give calixarenes with alkoxyhydroxyphosphoryl
fragments.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1102–1106, June, 2007. 相似文献
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新型杯[4]芳烃衍生物的合成 总被引:1,自引:0,他引:1
以对叔丁基杯[4]芳烃为起始原料,通过一步或两步取代反应合成了对叔丁基杯[4]芳烃的衍生物(1和2),其结构经FT-IR,^1H NMR,FAB-MS表征. 相似文献
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New calix[4]resorcinarenes having two or four azobenzo-15-crown-5 residues on the lower rim have been synthesized by the condensation of resorcinol with the corresponding aldehyde (acetal). 相似文献